A peelable decontamination composite film capable of rapidly curing under sunlight and a preparation method thereof

Abstract

The present invention provides a peelable, decontamination-removing composite film capable of rapid curing under sunlight and a preparation method thereof. The peelable, decontamination-removing composite film comprises a peelable layer and a reinforcing layer. The peelable layer comprises 1 to 9 mol of monomer A, 1 to 9 mol of monomer B, 0.2 to 3 mol of a crosslinker, 0.01 to 1 mol of a photoinitiator, 1 to 60 mol of deionized water, 0.2 to 4 mol of dimethyl silicone oil, and 0.2 to 5 mol of a detergent. The reinforcing layer is a non-woven fabric or a polyethylene mesh. The preparation method comprises: mixing the monomers, crosslinker, photoinitiator, deionized water, dimethyl silicone oil, and detergent in a specific proportion to obtain a solution for the peelable layer; spraying the peelable layer solution onto the reinforcing layer, and irradiating the reinforcing layer with sunlight during the decontamination operation to obtain the peelable, decontamination-removing composite film. The peelable decontamination film provided by the present invention has the characteristics of no need for external light source, fast film formation, high strength, easy peeling, excellent tear resistance, and high film peeling rate. It can be sprayed and used under low temperature conditions, and is particularly suitable for the field of radioactive decontamination in high-altitude and cold areas.

Description

Technical Field

[0001] The present invention belongs to the technical field of radioactive decontamination, and in particular relates to a high-strength, low-temperature-resistant, peelable decontamination composite film that can be quickly solidified under sunlight and a preparation method thereof. Background Art

[0002] Nuclear technology is increasingly being applied in numerous fields, including civilian power generation, military, medical testing and treatment, and industrial flaw detection, becoming an indispensable component of national defense, production, and daily life. However, the processing and application of nuclear materials can lead to varying degrees of radioactive contamination. Existing radioactive decontamination materials primarily include dry-process removers, detergents, chemical foam / gel decontaminants, and peelable membrane materials. Peelable membrane decontamination offers advantages such as ease of spraying, easy peeling and recycling, zero waste generation, and amenable mechanization. These materials are suitable for rapid decontamination of buildings, roads, and large equipment and devices.

[0003] Currently, the more common peelable films are organic solvent type, water-soluble (emulsion) type and UV curing type. For example, the research group of Lin Xiaoyan published a peelable film with polyvinyl acetate as the main film-forming body and ethyl acetate as its organic solvent in the Journal of Southwest University of Science and Technology in 2020. Polyvinyl acetate needs to be dissolved in ethyl acetate and dried to form a film after the ethyl acetate evaporates. The drying time is relatively long, about 5-7 hours; the research group of Wang Shanqiang published a water-soluble peelable decontamination film prepared by copolymerizing three monomers, vinyl acetate, butyl acrylate, and polyvinyl alcohol, by a semi-continuous emulsion method in the Journal of Southwest University of Science and Technology in 2019. The water-soluble film material has the advantages of being non-toxic, harmless, and environmentally friendly, but the drying film-forming time exceeds 12 hours. In addition, when the temperature of the water-soluble (emulsion) system is below the freezing point, the water-soluble (emulsion) system will freeze or the polymer emulsion will demulsify, making the peelable film unable to be used below 0°C; the existing UV peelable composite film needs to be baked at high temperature in an oven for a period of time before being irradiated with ultraviolet light to form a film, but high-temperature baking cannot be achieved in field decontamination sites.

[0004] Furthermore, existing mechanized peelable films face two major challenges: poor peelability and tear resistance. Due to the strong adhesion between the peelable film and the ground, it is difficult to peel the film from the ground using a device. Furthermore, if the ground is uneven, holes can easily form during the curing process. Since the peelable film itself has poor tear resistance, the presence of holes makes the film easily ripped during the peeling process, leaving the torn film part on the ground. As a result, the overall peelability rate of the film is very low in actual mechanized operations. Summary of the Invention

[0005] (1) Technical issues to be solved

[0006] The present invention provides a peelable decontamination composite film that can be quickly cured under sunlight and a preparation method thereof, so as to solve the technical problems of poor tear resistance and low peeling rate of existing mechanized peelable films.

[0007] (2) Technical solution

[0008] In order to solve the above technical problems, the present invention proposes a peelable decontamination composite film that can be quickly cured under sunlight, wherein the peelable decontamination composite film includes a reinforcing layer and a peelable layer sprayed on the reinforcing layer; wherein, in terms of molar number, the raw material components of the peelable layer include: 1 to 9 mol of monomer A, 1 to 9 mol of monomer B, 0.2 to 3 mol of cross-linking agent, 0.01 to 1 mol of photoinitiator, 1 to 60 mol of deionized water, 0.2 to 4 mol of dimethyl silicone oil, and 0.2 to 5 mol of detergent; monomer A is one of acrylic acid, methacrylic acid, itaconic acid, trans-aconitic acid, and maleic anhydride; monomer B is one of acrylamide, methacrylamide, and vinylimidazole.

[0009] Furthermore, the molar ratio of monomer A to monomer B is (1:9) to (9:1).

[0010] Furthermore, the cross-linking agent is one of zirconium oxychloride octahydrate, zirconium sulfate, aluminum chloride hexahydrate, ferric chloride hexahydrate, zinc perchlorate hexahydrate, zinc sulfate heptahydrate, zinc nitrate hexahydrate, zinc iodide, and copper chloride dihydrate.

[0011] Furthermore, the photoinitiator is a visible light initiator.

[0012] Furthermore, the visible light initiator is two or three of camphorquinone, diphenylsilane, diphenyliodonium hexafluorophosphate, and 4-dimethylamino-ethyl benzoate.

[0013] Furthermore, the detergent is one or more of ethylenediaminetetraacetic acid, citric acid, and sodium dodecylbenzenesulfonate.

[0014] Furthermore, the reinforcement layer is non-woven fabric or polyethylene mesh.

[0015] In addition, the present invention also provides a method for preparing a peelable decontamination composite film, characterized in that the preparation method comprises the following steps:

[0016] S1 weighed the raw materials according to the above ratio, the monomer, crosslinker, photoinitiator, deionized water, dimethyl silicone oil and detergent in proportion to obtain a peelable layer solution;

[0017] S2. Spraying the strippable layer solution onto the reinforcing layer and irradiating it with sunlight during the decontamination operation to obtain a strippable decontamination composite film.

[0018] Furthermore, the sunlight exposure time is 5 to 30 minutes.

[0019] (3) Beneficial effects

[0020] The present invention provides a peelable, decontamination-removing composite film capable of rapid curing under sunlight and a preparation method thereof. The peelable, decontamination-removing composite film comprises a peelable layer and a reinforcing layer. The peelable layer is composed of the following components: 1-9 mol of monomer A, 1-9 mol of monomer B, 0.2-3 mol of a crosslinker, 0.01-1 mol of a photoinitiator, 1-60 mol of deionized water, 0.2-4 mol of dimethyl silicone oil, and 0.2-5 mol of a detergent. The reinforcing layer is a non-woven fabric or a polyethylene mesh. The preparation method of the peelable, decontamination-removing composite film comprises: mixing the monomers, crosslinker, photoinitiator, deionized water, dimethyl silicone oil, and detergent in a certain proportion to obtain a solution for the peelable layer; spraying the peelable layer solution onto the reinforcing layer, and irradiating the reinforcing layer with sunlight during the decontamination operation to obtain the peelable, decontamination-removing composite film. The peelable decontamination film provided by the present invention has the characteristics of no need for external light source, fast film formation, high strength, easy peeling, excellent tear resistance, and high film peeling rate. It can be sprayed and used under low temperature conditions, and is particularly suitable for the field of radioactive decontamination in high-altitude and cold areas.

[0021] The beneficial effects of the present invention are as follows:

[0022] 1. The peelable layer solution of the present invention maintains a low viscosity at -20°C. Therefore, even at an extreme temperature of -20°C, the peelable layer solution can be sprayed by machine without the need for roller coating, thus reducing the number of steps and saving manpower and material costs.

[0023] 2. The peelable layer in the present invention can be cured only by sunlight, without the need for external light sources and heating devices (such as traditional high-energy mercury lamps, ultraviolet lamps, ovens, etc.). The curing time is shortened to 5 to 30 minutes, which facilitates operation, reduces process steps, saves energy and environment, and saves manpower and material costs.

[0024] 3. Based on the metal coordination effect and the mechanism of metal salt lowering the freezing point of the solution, the peelable layer prepared by the present invention still has excellent strength and toughness at low temperatures, so the peelable layer can be used in extreme outdoor conditions of -20°C.

[0025] 4. The present invention uses the reinforcement layer as a carrier to form a sandwich structure (peelable layer-reinforcement layer-peelable layer) between the reinforcement layer and the peelable layer. When peeling by machine, the peelable layer can be completely separated from the ground by simply dragging up the reinforcement layer, thereby improving the overall peelability of the membrane body. The peelability rate is above 99.9%. At the same time, the high-strength reinforcement layer is used as support to fundamentally solve the problem of easy tearing of the peelable membrane.

[0026] 5. The peelable decontamination composite film provided by the present invention is particularly suitable for rapid radioactive decontamination in high-altitude and cold areas. It can be sprayed even at -20°C without the need for external light sources and heating equipment. It can form a film quickly only by irradiation with sunlight. The film has the characteristics of high strength, high toughness, excellent tear resistance, easy peeling, and high film-forming peeling rate at -20°C. DETAILED DESCRIPTION

[0027] In order to make the purpose, content and advantages of the present invention more clear, the specific implementation methods of the present invention are further described in detail below with reference to the embodiments.

[0028] The present invention provides a high-strength, low-temperature-resistant, peelable, decontamination-removing composite film that can be quickly cured under sunlight. The peelable, decontamination-removing composite film includes a reinforcing layer and a peelable layer sprayed on the reinforcing layer. The raw material components of the peelable layer include, in molar terms, 1 to 9 mol of monomer A, 1 to 9 mol of monomer B, 0.2 to 3 mol of a cross-linking agent, 0.01 to 1 mol of a photoinitiator, 1 to 60 mol of deionized water, 0.2 to 4 mol of dimethyl silicone oil, and 0.2 to 5 mol of a detergent.

[0029] Monomer A is selected from the group consisting of acrylic acid (AAc), methacrylic acid (MAAc), itaconic acid (IAc), trans-aconitic acid (ACAc), and maleic anhydride (MAH). The selected monomer contains a carboxylate group, which can coordinate with the metal salt, providing high strength to the peelable layer. Monomer B is selected from the group consisting of acrylamide (AAm), methacrylamide (MAAm), and vinylimidazole (VI). The selected monomer contains a C=C double bond, allowing copolymerization with monomer A. The hydrogen bonding between the monomer and monomer A further enhances the strength of the peelable layer.

[0030] In the present invention, the molar ratio of monomer A to monomer B is (1:9) to (9:1). If the molar ratio of monomer A to monomer B is too low, the viscosity of the peelable layer solution will increase, which is not conducive to spraying; if the molar ratio of monomer A to monomer B is too high, the strength of the peelable layer will be too low.

[0031] In the present invention, the crosslinking agent is one of zirconium oxychloride octahydrate (ZrOCl2·8H2O), zirconium sulfate (Zr(SO4)2), aluminum chloride hexahydrate (AlCl3·6H2O), ferric chloride hexahydrate (FeCl3·6H2O), zinc perchlorate hexahydrate (Zn(ClO4)2·6H2O), zinc sulfate heptahydrate (ZnSO4·7H2O), zinc nitrate hexahydrate (Zn(NO3)2·6H2O), zinc iodide (ZnI2), and copper chloride dihydrate (CuCl2·2H2O). The selected monomer contains a metal ion that can coordinate with monomer A, providing high strength to the peelable layer. The selected metal salt can lower the freezing point of the solution, resulting in good low-temperature flow and sprayability of the peelable layer solution at -20°C. Furthermore, the prepared peelable layer still exhibits excellent strength and toughness at -20°C. The cross-linking agent content is 0.2 to 3 mol. If the cross-linking agent content is too low, the cross-linking degree between functional groups will be reduced, thereby reducing the strength of the peelable layer; if the cross-linking agent content is too high, excessive cross-linking between functional groups will result, which will make the peelable layer brittle and reduce the mechanical properties.

[0032] In the present invention, the photoinitiator is two or three of camphorquinone CQ, diphenylsilane DPS, diphenyliodonium hexafluorophosphate Iod, and ethyl 4-dimethylaminobenzoate EDB. All of the selected photoinitiators are visible light initiators. The photoinitiator content is 0.01 to 1 mol. If the photoinitiator content is too low, the free radical chain growth rate during the photopolymerization reaction will be far lower than the chain termination rate due to oxygen inhibition, resulting in a prolonged induction period of the photopolymerization reaction, a slow reaction rate, or even no reaction. If the photoinitiator content is too high, the molecular weight distribution of the polymerized product will become broad, resulting in a lower molecular weight.

[0033] In the present invention, the content of deionized water is 1 to 60 mol. If the content of deionized water is too low, the viscosity of the peelable layer solution will become high, which is not conducive to spraying; if the content of deionized water is too high, the strength of the peelable layer will be too low.

[0034] In the present invention, the dimethyl silicone oil is 0.2 to 4 mol. If the dimethyl silicone oil content is too low, it will not reduce the surface energy of the film and reduce the bonding strength between the film and the medium, and thus cannot improve the peelability of the film; if the dimethyl silicone oil accounts for too high a proportion in the system, it will hinder the cross-linking reaction between the monomers, making the system difficult to solidify.

[0035] In the present invention, the detergent is one or more of ethylenediaminetetraacetic acid EDTA, citric acid CA, and sodium dodecylbenzenesulfonate SDBS. EDTA can remove K + , Rb + 、Cs +CA can form stable water-soluble chelates with any metal ions other than 1% hydroxybenzoic acid (NH4Cl2). CA can ionize a certain amount of hydrogen ions, changing the value of the detergent sol, thereby facilitating the coordination of the complexing agent. Its polycarboxyl structure can also form complex ions with metal ions. SDBS sodium dodecylbenzenesulfonate is an anionic surfactant that can coordinate with metal ions, improving decontamination efficiency. It also helps improve the strippability of the decontamination film and enhance the stability of the detergent. The detergent content is 0.2 to 5 mol; too low a detergent content will not effectively remove surface contamination. With increasing detergent concentration, the decontamination rate first gradually increases and then remains essentially unchanged.

[0036] In the present invention, the reinforcement layer is non-woven fabric or polyethylene mesh.

[0037] The method for preparing the above-mentioned peelable decontamination composite film comprises the following steps:

[0038] S1 weighed raw materials according to the ratio, the monomer, crosslinker, photoinitiator, deionized water, dimethyl silicone oil and detergent in proportion to obtain a strippable layer solution;

[0039] S2. Spraying the peelable layer solution onto the reinforcing layer and irradiating it with sunlight to obtain a peelable decontamination composite film.

[0040] The raw materials used in Examples 1-3 are: acrylic acid (>99%, ALADDIN, CAS#79-10-7), methacrylic acid (=>99%, ALADDIN, CAS#79-41-4), itaconic acid (>99%, ALADDIN, CAS#97-65-4), acrylamide (>99%, ALADDIN, CAS#79-06-1), methacrylamide (>98%, ALADDIN, CAS#79-39-0), vinylimidazole (>99%, ALADDIN, CAS#1072-63-5), zirconium oxychloride octahydrate (>99%, ALADDIN, CAS#13520-92-8), aluminum chloride hexahydrate (>97%, ALADDIN, CAS#7784-13-6), zinc perchlorate hexahydrate (>99%, ALADDIN, CAS#10025-54-6), camphor Brainquinone (>98%, ALADDIN, CAS#10373-78-1), diphenylsilane (>97%, ALADDIN, CAS#775-12-2), ethyl p-dimethylaminobenzoate (>97%, ALADDIN, CAS#775-12-2), diphenyliodonium hexafluorophosphate (>97%, TCI, CAS#58109-40-3), dimethicone (Greagent, CAS#63148-62-9), ethylenediaminetetraacetic acid (>98%, Aldrich, CAS#304695-78-1), citric acid (>99.5%, ALADDIN, CAS#77-92-9), sodium dodecylbenzenesulfonate (>95%, ALADDIN, CAS#25155-30-0), uranyl nitrate hexahydrate (>99%, Bore, CAS#36478-76-9).

[0041] The method for determining the tensile strength of the decontamination composite membrane is as follows: cut the peelable decontamination composite membrane into rectangular specimens with a width of 2 cm and a length of 6 cm, set the specimen gauge length to 2 cm on a computer-controlled electronic universal testing machine, then vertically clamp the specimen and stretch it at a speed of 2 mm / min until it breaks, and obtain the tensile strength and elongation at break of the peelable decontamination composite membrane.

[0042] The decontamination efficiency of the decontamination composite membrane is determined by spraying the peelable decontamination composite membrane onto a sample contaminated with uranyl nitrate and irradiating it with light to form a film. The membrane is then removed, and the residual radioactivity of the sample after decontamination is measured and compared with the radioactivity measured on the sample before decontamination. The decontamination efficiency η is calculated using the following formula.

[0043]

[0044] Where η is the decontamination rate after coating decontamination, A0 is the radioactivity of the original contamination, and A1 is the residual radioactivity after coating decontamination.

[0045] Example 1

[0046] A peelable, decontamination-resistant composite film was prepared by mixing 3 mol of acrylic acid (AAc), 7 mol of acrylamide (AAm), 1 mol of zirconium oxychloride octahydrate (ZrOCl2·8H2O), 0.05 mol of camphorquinone (CQ), 0.05 mol of diphenylsilane (DPS), 0.05 mol of diphenyliodonium hexafluorophosphate (Iod), 11 mol of deionized water, 1 mol of dimethyl silicone oil, 4 mol of ethylenediaminetetraacetic acid (EDTA), and 2 mol of sodium dodecylbenzenesulfonate (SDBS). The mixture was sprayed onto a non-woven surface and exposed to midday winter sunlight for 6 minutes. The tensile strength of the composite film was measured in a -20°C chamber and the results were 10.6±2.4 MPa, 20.0±14.4% elongation at break, and 176.2±36.8% elastic modulus. The decontamination rate of the decontamination composite film on the glass surface reached 99.92%, and the decontamination rate on the cement surface reached 86.67%. The stripping rate of the decontamination composite film was 100%.

[0047] Example 2

[0048] A peelable decontamination composite film was prepared by mixing 1 mol of itaconic acid (IAc), 9 mol of methacrylamide (MAAm), 0.2 mol of aluminum chloride hexahydrate (AlCl3·6H2O), 0.01 mol of camphorquinone (CQ), 0.01 mol of ethyl 4-dimethylaminobenzoate (EDB), 0.01 mol of diphenyliodonium hexafluorophosphate (Iod), 60 mol of deionized water, 0.2 mol of dimethyl silicone oil, 5 mol of citric acid (CA), and 0.2 mol of sodium dodecylbenzenesulfonate (SDBS). The mixture was sprayed onto a polyethylene mesh surface and exposed to sunlight at 8:00 a.m. in winter for 26 minutes. The tensile strength of the composite film was measured in a -20°C test chamber. The results showed a strength of 8.0±1.4 MPa, an elongation at break of 68.9±18.2%, and an elastic modulus of 38.3±2.6%. The decontamination rate of the decontamination composite film on the glass surface reached 99.70%, and the decontamination rate on the cement surface reached 86.45%. The stripping rate of the decontamination composite film was 100%.

[0049] Example 3

[0050] A peelable, decontamination-removing composite film was prepared by mixing 9 mol of methacrylic acid (MAAc), 1 mol of vinylimidazole (VI), 3 mol of zinc perchlorate hexahydrate (Zn(ClO4)2·6H2O), 1 mol of camphorquinone (CQ), 1 mol of ethyl 4-dimethylaminobenzoate (EDB), 1 mol of deionized water, 4 mol of dimethyl silicone oil, and 1 mol of ethylenediaminetetraacetic acid (EDTA). The mixture was sprayed onto a non-woven surface and exposed to sunlight at 10:00 AM in winter for 10 minutes. The tensile strength of the composite film was measured in a -20°C chamber and revealed a strength of 7.0±0.7 MPa, an elongation at break of 21.1±3.7%, and an elastic modulus of 44.7±1.2%. The composite film achieved a decontamination rate of 97.37% on glass and 80.38% on cement. The decontamination-removing composite film also achieved a 100% peelability.

[0051] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A peelable decontamination composite film that can be quickly cured under sunlight, characterized in that: The peelable decontamination composite film includes a reinforcing layer and a peelable layer sprayed on the reinforcing layer; wherein, in terms of molar number, the raw material components of the peelable layer include: 1-9 mol of monomer A, 1-9 mol of monomer B, 0.2-3 mol of a crosslinker, 0.01-1 mol of a photoinitiator, 1-60 mol of deionized water, 0.2-4 mol of dimethyl silicone oil, and 0.2-5 mol of a detergent; the monomer A is one of acrylic acid, methacrylic acid, itaconic acid, trans-aconitic acid, and maleic anhydride; the monomer B is one of acrylamide, methacrylamide, and vinylimidazole; the crosslinker is one of zirconium oxychloride octahydrate, zirconium sulfate, aluminum chloride hexahydrate, ferric chloride hexahydrate, zinc perchlorate hexahydrate, zinc sulfate heptahydrate, zinc nitrate hexahydrate, zinc iodide, and copper chloride dihydrate; the photoinitiator is a visible light initiator, and the visible light initiator is two or three of camphorquinone, diphenylsilane, diphenyliodonium hexafluorophosphate, and 4-dimethylamino-ethyl benzoate.

2. The peelable decontamination composite film according to claim 1, wherein The molar ratio of monomer A to monomer B is (1:9) to (9:1).

3. The peelable decontamination composite film according to claim 1, wherein The detergent is one or more of ethylenediaminetetraacetic acid, citric acid, and sodium dodecylbenzenesulfonate.

4. The peelable decontamination composite film according to claim 1, wherein The reinforcement layer is non-woven fabric or polyethylene mesh.

5. A method for preparing a peelable decontamination composite film according to any one of claims 1 to 4, characterized in that: The preparation method comprises the following steps: S1. Weigh the raw materials according to the ratio of claim 1, and mix the monomer, crosslinker, photoinitiator, deionized water, dimethyl silicone oil and detergent in proportion to obtain a peelable layer solution; S2. Spraying the strippable layer solution onto the reinforcing layer and irradiating it with sunlight during the decontamination operation to obtain a strippable decontamination composite film.

6. The method for preparing a peelable decontamination composite film according to claim 5, wherein: The sunlight irradiation time is 5 to 30 minutes.

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